integration of solid oxide fuel cells and ... - Ea Energianalyse

8. CONCLUSION
So by looking at how the effectiveness depends on NTU, these heat
exchangers were optimized to what could reasonably be expected to be
possible.
The sensitivity analysis showed that the pressure loss and heat loss
of the components in the ABS unit were not so influential, so neglecting
these were probably not a significant source to uncertainty.
The temperature of the evaporator turned out not to be as important
as one would expect for a cooling device. If the temperature of the cooled
fluid out of the evaporator is increased from 5 ◦ C to 30 ◦ C the amount of
generated cooling only increases by 1/5. So compared to an electrical
unit, the ABS is most advantageous for low temperatures (where the
COP of an ECH decreases more rapidly). But of course the temperature
may not be below 0 ◦ C for water-LiBr ABS unit since the water would
freeze.
Performance
When the model was optimized with respect to the different temperatures
and the effectiveness of heat exchangers etc. the following performance
was obtained for a 100kW fuel (methane) input:
• 50kW of electricity.
• 59kW of cooling.
• 3kW of heat for hot water production.
• 112kW total (Sum of total services).
If instead the waste heat had been used for hot water production only,
the system would have given less than 100kW of total services (i.e. 50kW
of electricity and approximately 45kW of hot water). So by utilizing
the ABS unit, the amount of total services per kW fuel input has been
increased, and furthermore the value of the cooling is often higher than
that of heating.
Market segments, Economics and Climate
The market investigations indicated a potential economical advantage by
using a SOFC-ABS system in two of the three market segments:
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